The invention concerns a coiler mandrel with radially displaceable expansion segments and/or closing bars arranged on its periphery and a method for locking/clamping the expansion segments and/or closing bars.
Coiling installations are used, for example, for coiling rolled sheet or other materials onto a coiler mandrel and/or for uncoiling a coil. To carry out a coiling operation, the expansion segment is displaced radially outward in such a way that the outer periphery of the expansion segments forms a circle. To uncoil a coil, the coiler mandrel must be smaller in diameter than the inside diameter of the coil in order to hold the coil. To this end, in a coiler mandrel, two diameters can usually be systematically moved into, where only an expanded, maximum diameter has a completely circular configuration.
In previous designs of coiler mandrels of this type, coiler segments are radially displaced by means of wedge surfaces, which are moved by means of push or pull rods. In another previously known design, coiler shell portions are moved about an external center of rotation by means of cylinders.
DE 35 02 452 A1 describes a coiling and/or uncoiling coiler for rolled strip, with a drum that consists of several expansible segments, which are supported with wedge-shaped sliding surfaces against a coiler shaft that is rotatably supported in a coiler housing. A ram is guided in the coiler shaft and is connected with the drum segments by means of a connecting flange. In this regard, an actuator effects a relative axial displacement between the coiler shaft and the ram, which is connected with the segments, and this displacement produces an expanding movement of the segments. In addition, the coiler has a displacing drive that causes the coiler drum to be pushed in and out relative to the strip coil and/or that effects strip center regulation, where the coiler shaft is supported in a stationary coiler housing in a way that allows it to be axially displaced, the actuator has a piston-cylinder unit, which cannot rotate relative to the stationary coiler housing but can be axially displaced for the contracting action of the coiler shaft, a compression spring always keeps the segments in the expanded state, and the displacing drive consists of a piston-cylinder unit, by means of which the coiler shaft can be acted upon to be axially displaced.
EP 0 504 296 B1 discloses a coiler for coiling and/or uncoiling metal strip with strip tension forces of 10 to 1000 kN. It consists of an expandable winding drum, which is supported by a hollow shaft that is mounted on two bearings in a stator. The winding drum is actuated by an actuating cylinder mounted on the hollow shaft via a driving rod that passes through the hollow shaft. A drive motor, which consists of a stator and a rotor and is mounted between the two bearings of the hollow shaft, is coupled to the hollow shaft. In this regard, the hollow shaft is designed as the rotor shaft, and the driving rod is designed as the winding drum shaft supported in the hollow shaft.
German Early Disclosure 1 777 229 describes an expandable coiler mandrel for coiling rolled strip, especially hot-rolled strip, with an inner mandrel body and several expansion segments placed on it. These expansion segments are supported by push rods on wedge surfaces of a wedge bar that is concentrically supported in the mandrel body and that has a number of wedge surfaces, such that the expansion segments are joined by tabs with a wedge bar that is concentrically mounted in the mandrel body.
DE 30 28 607 C2 discloses a rolled strip coiler, which already has a ram that is pretensioned by spring force and held in its expanded position. The ram is acted upon by means of an actuator that is mounted in a stationary and rotationally rigid way in such a way that the segments can be contracted.
The previously known embodiments and designs all require expensive maintenance and servicing. Wedge surface designs must remain in a narrow range in their friction behavior, since otherwise malfunctions occur, such as jamming or shifting of the segments under a load, and this in turn can result in loss of production.